Integrated circuit with temperature sensor and method for heating the circuit

ABSTRACT

A temperature sensor is integrated together with an integrated circuit on a chip, the sensor delivering a temperature-dependent measuring signal or at least emitting a signal when the chip temperature falls below a specific prescribed value. For such an eventuality, the chip includes a special circuit device thereon, by which a current flow is generated through a provided structure of electrical conductors that keeps the temperature of the integrated circuit above a prescribed minimum temperature.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of copending InternationalApplication No. PCT/DE01/02802, filed Jul. 24, 2001, which designatedthe United States and was not published in English.

BACKGROUND OF THE INVENTION

[0002] Field of the Invention

[0003] The invention relates to an integrated circuit on a semiconductorchip in which a temperature sensor is integrated and a method forheating the circuit.

[0004] Integrated circuits work in a very wide temperature range. If thecircuit is required to work perfectly at very low temperatures as well,individual specimens of the circuit must also be tested at lowtemperatures at least by random sampling. But this additional selectionsubstantially decreases the yield of usable circuits. Such a problemoccurs particularly with memory modules such as DRAMs.

SUMMARY OF THE INVENTION

[0005] It is accordingly an object of the invention to provide anintegrated circuit with temperature sensor and a method for heating thecircuit that overcome the hereinafore-mentioned disadvantages of theheretofore-known devices and methods of this general type and that has ahigh operational reliability even at low temperatures.

[0006] With the foregoing and other objects in view, there is provided,in accordance with the invention, an integrated circuit on asemiconductor chip, including an integrated temperature sensor detectinga temperature of the semiconductor chip and providing a measuredtemperature signal, a structure of electrical conductors, and a specialcircuit device connected to the integrated temperature sensor and to atleast some of the conductors, the special circuit device generating,dependent upon the measured temperature signal, current flow through theat least some of the conductors when the detected temperature fallsbelow a given temperature value.

[0007] In the inventive integrated circuit on a semiconductor chip, atleast one temperature sensor is integrated on the chip together with thecircuit, which sensor delivers a temperature-dependent measuring signalor at least emits a signal when the chip temperature falls below aspecific prescribed value. For this eventuality, a special circuitdevice is provided on the chip, which brings about a current flowthrough a provided structure of electrical conductors, therebygenerating heat in a sufficient quantity to hold the temperature of theintegrated circuit above a prescribed minimum temperature. Not only doessuch an integrated circuit increase the yield of chips that functionperfectly at low temperatures, but it also can be used at lowertemperatures than have been possible hitherto.

[0008] The structure of electrical conductors is simply to be configuredsuch that the current flowing through generates a sufficient quantity ofheat the ohmic resistance of the conductor so as to achieve the desiredthermal effect. These conductors can be the conductive tracks that areprovided on an integrated circuit anyway, these being conductivelyconnected to the special circuit device for generating the current flowas needed.

[0009] In a semiconductor memory, the conductors of individual memoryblocks (banks) that are not needed for a presently occurring store orwrite operation can be utilized. The conductors are the address linesover which the stored signals are sent to the memory cells or readtherefrom. Which banks of the memory chip are currently available forgenerating a heating current is determined by the drive circuit of thememory. The special circuit device is interconnected, as required, withthe conductors of the deactivated memory blocks, which are not beingused at present.

[0010] In accordance with another feature of the invention, there isprovided a memory having operating states, subregions, and addresslines, the conductors forming at least some of the address lines in arespective one of the subregion, the at least some of the address linesconnected to the special circuit device, preferably, according to atleast one of the operating states of the memory.

[0011] In accordance with a further feature of the invention, there isprovided a memory cell field having a margin and dummy cells aredisposed at the margin and form at least some of the conductors.

[0012] In accordance with an added feature of the invention, there isprovided a margin, the conductors being formed by dummy cells at themargin.

[0013] In accordance with an additional feature of the invention, thespecial circuit device is programmed to drive the memory and to modifythe operating states of the memory.

[0014] In accordance with yet another feature of the invention, thespecial circuit device is programmed to drive the memory and to modifyoperating states of the memory.

[0015] In accordance with yet a further feature of the invention, thespecial circuit device is to be driven by external commands to modifythe operating states of the memory.

[0016] In accordance with yet an added feature of the invention, thespecial circuit device is programmed to drive the memory with activateand precharge commands and to modify the operating states of the memory.

[0017] In accordance with yet an additional feature of the invention,the special circuit device to be driven by external activate andprecharge commands to modify an operating state of the memory.

[0018] In accordance with again another feature of the invention, thespecial circuit device generates signals in at least one given operatingstate of the memory effectuating a cutoff of current flow in at leastsome of the conductors when current is flowing through the conductors.

[0019] In accordance with again a further feature of the invention, theintegrated circuit has operating states and the special circuit devicegenerates signals effectuating a cutoff of current flow in at least oneof the operating states in at least some of the conductors when currentis flowing through the conductors.

[0020] With the objects of the invention in view, in a semiconductorchip, there is also provided an integrated circuit including anintegrated temperature sensor detecting a temperature of thesemiconductor chip and providing a measured temperature signal, astructure of electrical conductors, and a special circuit deviceconnected to the integrated temperature sensor and to at least some ofthe conductors, the special circuit device generating current flowthrough the at least some of the conductors when the detectedtemperature falls below a given temperature value.

[0021] With the objects of the invention in view, there is also provideda method for heating an integrated circuit, including the steps ofproviding a semiconductor chip having a structure of electricalconductors, integrated temperature sensor, and the integrated circuit,detecting a temperature of the semiconductor chip with the integratedtemperature sensor and generating a measured temperature signal,connecting a special circuit device to the integrated temperature sensorand to at least some of the conductors, and generating, dependent uponthe measured temperature signal, current flow with the special circuitdevice through the at least some conductors when the detectedtemperature falls below a given temperature value.

[0022] Other features that are considered as characteristic for theinvention are set forth in the appended claims.

[0023] Although the invention is illustrated and described herein asembodied in an integrated circuit with temperature sensor and a methodfor heating the circuit, it is, nevertheless, not intended to be limitedto the details shown because various modifications and structuralchanges may be made therein without departing from the spirit of theinvention and within the scope and range of equivalents of the claims.

[0024] The construction and method of operation of the invention,however, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The FIGURE is a schematic plan view of an exemplary integratedcircuit according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Referring now to the single FIGURE of the drawing, it is seenthat several temperature sensors 1 are disposed on the top surface ofthe semiconductor chip. The electrical conductors 2 are formed by theaddress lines 3 of a respective inactive subregion 4 of a memory or bydummy cells 10 at the margin of the memory cell field. The differentbanks 5 of the memory are not all active at the same time. Therefore,the conductors provided in the inactive banks can be utilized forheating the chip. The selection of the conductors and the generation ofthe current flow occur in the special circuit device 6, which isdiagrammatically illustrated in the FIGURE. Like the elements of thedrive circuit of the memory, the electronic elements of the specialcircuit device 6 can, for example, also be disposed between the memorybanks or at the margin of the semiconductor chip.

[0027] In principle, temperature sensor 1 can be any microelectronicintegratable temperature sensor. Such components are known per se andhave long been integrated on one chip with the appertaining componentsof an electronic drive and evaluation circuit. Thus, the inventiveintegrated circuit makes no additional demands from the standpoint offabrication technology.

[0028] The only demand on the electrical conductor that is utilized forheat generation is that it have a suitably high ohmic resistance and beso structured that the generated heat reaches the regions of the chipthat require heat. It is not necessary that the conductor connect thepoles of the applied potential difference to one another. In asemiconductor chip, in particular, it is advantageous to utilize asufficiently large capacity that is already present on the chip, whichcan be formed by contact surfaces, by charging it with an alternatingcurrent (a.c.) voltage with a sufficiently high frequency. Because thecapacity acts increasingly like a short circuit as the a.c. voltagefrequency rises, a sufficiently large current flow for heating the ohmicresistances of the supply lines can also be generated this way.

[0029] In semiconductor chips that are provided as memory chips for aDRAM, it is possible to realize a heating function by refresh cyclesthat follow one another in rapid succession. One possible implementationof such a heating function makes use of the presently inactive regionsof the memory banks (e.g., four segments of the on-chip banks areavailable in a standard SDRAM), which are utilized for heating and areoperated by activate and precharge commands.

[0030] To prevent a possible data loss due to the high demand on thememory cells, it is possible, additionally or preferably exclusively, toutilize the dummy cells 10 at the margin of the memory cell field forthe heat generation. These dummy cells 10 are usually provided toimprove the optical characteristics of the chip at the cell field marginfor the lithography processing steps. Because they, generally, do nothave their own electrical function, they are preferred as heatconductors.

[0031] The heating function that is controlled by the special circuitdevice can also be interrupted by external commands (activate,precharge, read, etc.) if need be so that the functionality of aninventive memory cell configuration is not compromised. In particular,the heating function can be indicated by a signal that is generated bythe special circuit device when there is current flowing though the heatconductors provided for such a purpose. This signal can be supplied toan external circuit that interrupts the heating if need be. Preferably,in certain provided operating states of the integrated circuit, theinterruption of the current flow occurs automatically by the specialcircuit device itself. The special circuit device is, then, provided forcontrolling the overall heating function so as not to compromise thefunction of the actual integrated circuit of the semiconductor chip inany way, but, rather, merely to provide for a minimum chip temperaturethat guarantees the correct operating mode.

We claim:
 1. An integrated circuit on a semiconductor chip, comprising:an integrated temperature sensor detecting a temperature of thesemiconductor chip and providing a measured temperature signal; astructure of electrical conductors; and a special circuit deviceconnected to said integrated temperature sensor and to at least some ofsaid conductors, said special circuit device generating, dependent uponsaid measured temperature signal, current flow through said at leastsome of said conductors when said detected temperature falls below agiven temperature value.
 2. The integrated circuit according to claim 1,including a memory having operating states, subregions, and addresslines, said conductors forming at least some of said address lines in arespective one of said subregions, said at least some of said addresslines connected to said special circuit device according to at least oneof said operating states of said memory.
 3. The integrated circuitaccording to claim 1, including a memory having operating states,subregions, and address lines, said conductors forming at least some ofsaid address lines in a respective one of said subregions, said at leastsome of said address lines connected to said special circuit device. 4.The integrated circuit according to claim 1, including: a memory cellfield having a margin; and dummy cells being disposed at said margin andforming at least some of said conductors.
 5. The integrated circuitaccording to claim 2, including: a memory cell field having a margin;and dummy cells being disposed at said margin and forming at least someof said conductors.
 6. The integrated circuit according to claim 3,including: a memory cell field having a margin; and dummy cells beingdisposed at said margin and forming at least some of said conductors. 7.The integrated circuit according to claim 1, including a margin, saidconductors being formed by dummy cells at said margin.
 8. The integratedcircuit according to claim 2, wherein said special circuit device isprogrammed to drive said memory and to modify said operating states ofsaid memory.
 9. The integrated circuit according to claim 3, whereinsaid special circuit device is programmed to drive said memory and tomodify operating states of said memory.
 10. The integrated circuitaccording to claim 2, wherein said special circuit device is to bedriven by external commands to modify said operating states of saidmemory.
 11. The integrated circuit according to claim 3, wherein saidspecial circuit device to be driven by external commands to modify anoperating state of said memory.
 12. The integrated circuit according toclaim 2, wherein said special circuit device is programmed to drive saidmemory with activate and precharge commands and to modify said operatingstates of said memory.
 13. The integrated circuit according to claim 3,wherein said special circuit device is programmed to drive said memorywith activate and precharge commands and to modify operating states ofsaid memory.
 14. The integrated circuit according to claim 2, whereinsaid special circuit device is to be driven by external activate andprecharge commands to modify said operating states of said memory. 15.The integrated circuit according to claim 3, wherein said specialcircuit device to be driven by external activate and precharge commandsto modify an operating state of said memory.
 16. The integrated circuitaccording to claim 1, wherein said special circuit device generatessignals in at least one given operating state of said memoryeffectuating a cutoff of current flow in at least some of saidconductors when current is flowing through said conductors.
 17. Theintegrated circuit according to claim 1, wherein: the integrated circuithas operating states; and said special circuit device generates signalseffectuating a cutoff of current flow in at least one of said operatingstates in at least some of said conductors when current is flowingthrough said conductors.
 18. In a semiconductor chip, an integratedcircuit comprising: an integrated temperature sensor detecting atemperature of the semiconductor chip and providing a measuredtemperature signal; a structure of electrical conductors; and a specialcircuit device connected to said integrated temperature sensor and to atleast some of said conductors, said special circuit device generatingcurrent flow through said at least some of said conductors when saiddetected temperature falls below a given temperature value.
 19. A methodfor heating an integrated circuit, which comprises: providing asemiconductor chip having a structure of electrical conductors,integrated temperature sensor, and the integrated circuit; detecting atemperature of the semiconductor chip with the integrated temperaturesensor and generating a measured temperature signal; connecting aspecial circuit device to the integrated temperature sensor and to atleast some of the conductors; and generating, dependent upon themeasured temperature signal, current flow with the special circuitdevice through the at least some conductors when the detectedtemperature falls below a given temperature value.